Steady Flow Generated by a Core Oscillating in a Rotating Spherical Cavity
Steady flow generated by oscillations of an inner solid core in a fluid-filled rotating spherical cavity is experimentally studied. The core with density less than the fluid density is located near the center of the cavity and is acted upon by a centrifugal force. The gravity field directed perpendicular to the rotation axis leads to a stationary displacement of the core from the rotation axis. As a result, in the frame of reference attached to the cavity, the core performs circular oscillation with frequency equal to the rotation frequency, and its center moves along a circular trajectory in the equatorial plane around the center of the cavity. For the differential rotation of the core to be absent, one of the poles of the core is connected to the nearest pole of the cavity with a torsionally elastic, flexible fishing line. It is found that the oscillation of the core generates axisymmetric azimuthal fluid flow in the cavity which has the form of nested liquid columns rotating with different angular velocities. Comparison with the case of a free oscillating core which performs mean differential rotation suggests the existence of two mechanisms of flow generation (due to the differential rotation of the core in the Ekman layer and due to the oscillation of the core in the oscillating boundary layers).
Keywordsrotation inner core oscillation steady flow differential rotation inertial waves
Unable to display preview. Download preview PDF.
- 1.G. S. Golitsyn, Introduction to the Dynamics of Planetary Atmospheres (Gidrometeoizdat, Leningrad, 1973) [in Russian].Google Scholar
- 2.P. Cardin and P. Olson, Experiments on Core Dynamics (Elsevier, New York, 2007), 319–343. (Treatise on Geophysics, Vol. 8).Google Scholar
- 3.Yu. N. Belyaev and I. M. Yavorskaya, “Viscous Flow in a Rotating Spherical Layer and Their Stability,” Itogi Nauki Tekh., Ser. Mekh. Zhidk. Gaza 15 (1980).Google Scholar
- 5.D. Yu. Zhilenko and O. E. Krivonosova, “Quasi-Two-Dimensional and Three-Dimensional Turbulence in Rotating Spherical Layers of a Fluid,” Pis’ma Zh. Eksp. Teor. Fiz. 101 (8), 583–588 (2015).Google Scholar
- 8.C. G. Kozlov and N. V. Kozlov, and S. V. Subbotin, “Motion of a Fluid and a Solid Core in a Spherical Cavity Rotating in an External Force Field,” Dokl. Akad. Nauk 454 (2), 173–177 (2014).Google Scholar
- 15.W. Thielicke and E. J. Stamhuis, “PIVlab—Towards User-Friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB,” J. Open Res. Software 2 (1), e30 (2014).Google Scholar